CVE-2021-3493
Severity CVSS v4.0:
Pending analysis
Type:
Unavailable / Other
Publication date:
17/04/2021
Last modified:
19/02/2025
Description
The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges.
Impact
Base Score 3.x
8.80
Severity 3.x
HIGH
Base Score 2.0
7.20
Severity 2.0
HIGH
Vulnerable products and versions
CPE | From | Up to |
---|---|---|
cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:lts:*:*:* | 18.04 (excluding) | |
cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:lts:*:*:* | 18.04.1 (including) | 20.04 (excluding) |
cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:-:*:*:* | 20.10 (excluding) |
To consult the complete list of CPE names with products and versions, see this page
References to Advisories, Solutions, and Tools
- http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html
- http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html
- http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52
- https://ubuntu.com/security/notices/USN-4917-1
- https://www.openwall.com/lists/oss-security/2021/04/16/1
- http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html
- http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html
- http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52
- https://ubuntu.com/security/notices/USN-4917-1
- https://www.openwall.com/lists/oss-security/2021/04/16/1